This invention relates to sleeve gaskets for pipes and, more particularly, to adapters for providing a smooth sealing surface on a pipe which has external reinforcing ribs so that the surface of the pipe comprises a multiplicity of peaks and valleys.
Fluid conduits and, more particularly, sewer pipe, have been made from concrete. In recent years, there have been proposals to replace such concrete conduits with plastics due to the improved physical characteristics of plastic and the desirable strength-to-weight ratio compared to concrete. A major drawback in employing plastic conduit as a substitute for concrete is the cost of the plastic, particularly when employing smooth-walled plastic tubing as a substitute for smooth-walled concrete tubing having equivalent mechanical strength.
While corrugated tubing offers increased stiffness in the tube wall, the corrugated interior of the pipe presents undesirable flow characteristics within the conduit. An acceptable plastic conduit having desirable strength-to-weight ratios and acceptable cost factors is plastic tubing having a smooth-walled interior with external projecting reinforcing ribs which provide desirable hoop strength characteristics to the tubing and which do not add materially to the weight or cost of the conduit. Since pipe joint sealing gaskets are designed to provide a fluidtight joint between smooth-walled conduits and openings in rigid concrete structures, such as a manhole, a pipe section, a septic tank, or the like, the conventional sealing gaskets cannot perform their sealing function with respect to a ribbed conduit.